title: Volatility of organic aerosol: evaporation of ammonium sulfate/succinic acid aqueous solution droplets.
abstract: Condensation and evaporation modify the properties and effects of atmospheric aerosol particles. We studied the evaporation of aqueous succinic acid and succinic acid/ammonium sulfate droplets to obtain insights on the effect of ammonium sulfate on the gas/particle partitioning of atmospheric organic acids. Droplet evaporation in a laminar flow tube was measured in a Tandem Differential Mobility Analyzer setup. A wide range of droplet compositions was investigated, and for some of the experiments the composition was tracked using an Aerosol Mass Spectrometer. The measured evaporation was compared to model predictions where the ammonium sulfate was assumed not to directly affect succinic acid evaporation. The model captured the evaporation rates for droplets with large organic content but overestimated the droplet size change when the molar concentration of succinic acid was similar to or lower than that of ammonium sulfate, suggesting that ammonium sulfate enhances the partitioning of dicarboxylic acids to aqueous particles more than currently expected from simple mixture thermodynamics. If extrapolated to the real atmosphere, these results imply enhanced partitioning of secondary organic compounds to particulate phase in environments dominated by inorganic aerosol.
authors.affiliation: Department of Physics, University of Helsinki , P.O. Box 64, FI-00014, Helsinki, Finland.
authors.forename: Taina
authors.initials: T
authors.lastname: Yli-Juuti
authors.forename: Alessandro A
authors.initials: AA
authors.lastname: Zardini
authors.forename: Axel C
authors.initials: AC
authors.lastname: Eriksson
authors.forename: Anne Maria K
authors.initials: AM
authors.lastname: Hansen
authors.forename: Joakim H
authors.initials: JH
authors.lastname: Pagels
authors.forename: Erik
authors.initials: E
authors.lastname: Swietlicki
authors.forename: Birgitta
authors.initials: B
authors.lastname: Svenningsson
authors.forename: Marianne
authors.initials: M
authors.lastname: Glasius
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Worsnop
authors.forename: Ilona
authors.initials: I
authors.lastname: Riipinen
authors.forename: Merete
authors.initials: M
authors.lastname: Bilde
mesh_terms: D000336:Aerosols / Q000737:chemistry*; D000645:Ammonium Sulfate / Q000737:chemistry*; D001272:Atmosphere / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003998:Dicarboxylic Acids / Q000737:chemistry; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods; D008956:Models, Chemical; D009930:Organic Chemicals / Q000737:chemistry; D012996:Solutions; D019802:Succinic Acid / Q000737:chemistry*; D013816:Thermodynamics; D014835:Volatilization; D014867:Water
chemical_list: D000336:Aerosols; D003998:Dicarboxylic Acids; D009930:Organic Chemicals; D012996:Solutions; D014867:Water; D019802:Succinic Acid; D000645:Ammonium Sulfate